Composition for Metal Surface Treatment, Treating Liquid for Surface Treatment, Method of Surface Treatment, and Surface-Treated Metal Material

ABSTRACT

A surface-treating composition which is a treating liquid containing no ingredients harmful to the environment; such a treating liquid has been difficult to obtain with any conventional technique. The composition enables a coating film having excellent corrosion resistance after coating to be deposited through surface treatment on a surface of a metallic material, e.g., an iron-based metallic material. The composition, which is for the surface treatment of a metal comprising iron and/or zinc, comprises the following ingredients (A), (B), and (C): (A) a compound containing at least one element selected from the group consisting of titanium, zirconium, hafnium, and silicon; (B) a compound containing yttrium and/or a lanthanide element; and (C) nitric acid and/or a nitric acid compound. In the composition, the ratio of the total mass concentration B of the yttrium and/or lanthanide element in the ingredient (B) to the total mass concentration A of the element(s) in the ingredient (A), K1=B/A, is 0.05≦K1≦50 and the ratio of the total mass concentration C of nitrogen atoms in the ingredient (C) in terms of NO 3  concentration to the total mass concentration A, K2=C/A, is 0.01≦K2≦200.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 USC Sections 365(c) and 120 of International Application No. PCT/JP2005/022176, filed Dec. 2, 2005 and published Jun. 15, 2006 as WO 2006/062037 Al, which claims priority from Japanese Application No. JP 2004-356059 filed Dec. 8, 2004, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention pertains to a composition for surface treatment, treating liquid for surface treatment, method of surface treatment, and surface-treated metal materials obtained by said treatment method. The composition will allow deposition of a surface coating film with excellent corrosion resistance or bare corrosion resistance after coating the surface of metal material such as building materials and home electrical appliance materials.

DISCUSSION OF THE RELATED ART

The phosphoric acid zinc treatment method or the chromate treatment method is commonly used for deposition of a surface coating film on the surface of metal materials, which provides the metal with excellent corrosion resistance after coating. With the phosphoric acid zinc treatment method, a film providing excellent corrosion resistance can be deposited on a steel plate or zinc-plated steel plate such as a hot rolled steel plate or cold rolled steel plate.

However, the formation of sludge as a byproduct during the phosphoric acid zinc treatment is difficult to avoid. With the chromate treatment method, although sufficient performance can be ensured after coating, there is a tendency to avoid using this method from the standpoint of current environmental regulations because the treatment liquid contains harmful hexavalent chromium.

Therefore, techniques have been developed in recent years to provide the necessary corrosion resistance using a treatment liquid that contains no harmful components and in which sludge does not form. Such techniques involve coating the surface of the base material with a thin film of a metal such as zirconium. Surface treatment methods of the kind described below have been proposed in the prior art.

For example, in the method described in Japanese Patent Application No. 2000-204,485, a non-chrome coating for metal surface treatment that contains a compound having a nitrogen atom with a lone electron pair or that contains this nitrogen compound and a zirconium compound is used. The purpose of this method is to obtain a surface coating film with excellent corrosion resistance and adherence with the use of compositions that contain no harmful hexavalent chromium.

However, the use of this method is limited to metal base materials such as aluminum alloys. Moreover, it is difficult to use this method for coating a material with a complex structure because a coating drying process is required for the formation of the surface coating film.

In the method described in Japanese Patent Application No. 2[1990]-25,579, a surface treatment agent and a treatment bath containing selenium, zirconium, phosphoric acid, and fluorine compounds are used for the deposition of a surface coating film with excellent tight bonding and corrosion resistance after coating by means of a formation reaction.

The use of this method, as in the case of the method described in Japanese Patent Application No. 2000-204,485, is limited to aluminum or aluminum alloys, which are metal base materials already having excellent corrosion resistance. This method cannot be used for the deposition of a surface coating film on the surface of iron-based material or zinc-based material.

In the method described in Japanese Patent Application No. 2000-199,077, a metallic surface treatment composition consisting of a metal acetylacetonate and a water-soluble inorganic titanium compound or water-soluble inorganic zirconium compound is used for the deposition of a surface coating film with excellent corrosion resistance and adherence after coating. This method can be used to treat metal materials other than aluminum alloys, such as magnesium, magnesium alloys, zinc, and zinc plated alloys. However, this method cannot be used for the deposition of a surface coating film on the surface of iron-based metal materials such as hot rolled steel plate or cold rolled steel plate.

In addition, a metal surface treatment using a chromium-free coating type acid composition has been described in Japanese Patent Application No. 5[1993]-195,244. In this metal surface treatment method, an aqueous solution of components capable of forming a film with excellent corrosion resistance is coated on a metal surface and then a baking/drying process is carried out for fixing the formed film without a water washing process. Therefore, no chemical reaction is involved in the formation of the film and thus it is possible to use this method for the deposition of a film on the surface of metals such as hot rolled steel plate, cold rolled steel plate, zinc-plated steel plate, and aluminum alloys. However, with this method, the film is formed by coating and drying as in the case of the method described in Japanese Patent Application No. 2000-204,485 and thus it is difficult to achieve a uniform film coating on a material with a complex structure.

In Japanese Patent Application No. 2004-43913, a metal chemical conversion method using a treatment bath containing zirconium ion and/or titanium ion and fluorine ion is described. This method is applicable to iron-based metal materials as well as aluminum and zinc. However, this method requires using an oxidizing agent for controlling the iron ion concentration in the chemical conversion agent during the conversion process. Therefore, this method cannot be used to carry out a highly workable surface treatments capable of depositing a film with excellent corrosion resistance and adherence on metal materials such as iron-based metal materials, zinc-based metal materials, etc., using a treatment liquid containing none of the environmentally harmful components used in the conventional technique.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a composition for surface treatment, treating liquid for surface treatment, method of surface treatment, and surface-treated metal materials obtained by said treatment method. Said composition deposited on a metal surface provides bare corrosion resistance as well as excellent corrosion resistance after additional surface coating on the surface of metal materials, for example, iron-based metal materials such as hot rolled steel plate, cold rolled steel plate used in building materials and home electrical appliance materials, zinc-based metal materials such as zinc-plated steel plate, etc. Furthermore, said surface treatment method uses a treating liquid that contains none of the environmentally harmful components used in the conventional technique.

Applicants have carried out extensive studies on methods for solving the problems described above and were able to develop a composition for surface treatment, treating liquid for surface treatment, method of surface treatment, and surface-treated metal materials obtained by said treatment method, unlike those of the conventional techniques. The problems of the prior art discussed above are solved, at least in part, by the present inventions as described in below.

It is an object of the invention to provide a composition for the surface treatment of metals that comprise iron and/or zinc, the composition comprising:

-   -   (A) a compound containing at least one element selected from the         group consisting of Ti, Zr, Hf, and Si;     -   (B) a compound containing yttrium and/or a lanthanide element;         and     -   (C) nitric acid and/or a nitric acid compound.

In one embodiment of the composition, the ratio “K1” of the total mass concentration “B” of the yttrium and/or lanthanide element contained in Component (B) to the total mass concentration “A” of elements contained in Component (A), i.e., K1=B/A, is in the range of 0.05≦K1≦50 and the ratio “K2” of the total mass concentration “C” of the nitrogen atoms contained in Component (C) in terms of the NO₃ concentration to total mass concentration “A”, i.e., K2=C/A, is in the range of 0.01≦K2≦200.

A composition for surface treatment as described herein may also comprise Component (D), at least one fluorine-containing compound. Desirably, the free fluorine ion concentration “D” is in the range of 0.001 ppm≦D≦300 ppm.

A treatment liquid as described herein desirably has a pH value of no more than 6.0. [0019.] It is a further object of the invention to provide a composition for the surface treatment of metals that comprise iron and/or zinc, as described above, the composition also comprising at least one compound selected from the group consisting of HCl, H₂SO₄, HClO₃, HBrO₃, HNO₂, HMnO₄, HVO₃, H2O₂, H₂WO₄, H₂MoO₄ and their salts in a concentration in the range of 10-20,000 ppm.

It is a further object of the invention to provide a composition for the surface treatment of metals that comprise iron and/or zinc, as described above, that contains at least one compound selected from the group consisting of ethylenediamine tetraacetic acid, gluconic acid, heptogluconic acid, glycolic acid, citric acid, succinic acid, fumaric acid, aspartic acid, tartaric acid, malonic acid, malic acid, salicylic acid, and their salts in a concentration in the range of 1-1 0,000 ppm.

It is a further object of the invention to provide a composition for the surface treatment of metals that comprise iron and/or zinc, as described above, that contains a water-soluble polymer compound and/or a water- dispersible polymer compound.

It is a further object of the invention to provide a composition for the surface treatment of metals that comprise iron and/or zinc, as described above, that contains at least one surfactant selected from a group consisting of nonionic surfactants, anionic surfactants, and cationic surfactants.

It is an object of the invention to provide a surface treatment method for metals containing iron and/or zinc that includes a treatment liquid contact process in which a metal material containing iron and/or zinc is brought into contact with the treatment liquid for surface treatment described herein.

It is a further object of the invention to provide a surface treatment method for metals containing iron and/or zinc as described above, that includes a treatment liquid contact process in which a metal material containing iron and/or zinc is brought into contact with the treatment liquid to simultaneously carry out a degreasing treatment and a film formation treatment on metal material. In another embodiment, metal material that contains iron and/or zinc is a metal material that has been cleansed by a degreasing treatment.

It is a further object of the invention to provide a surface treatment method as described herein, in which treatment liquid contact process involves an electrolytic treatment using metal material that contains iron and/or zinc as a cathode.

It is a further object of the invention to provide a surface treatment method as described herein that includes a process in which the metal material that contains iron and/or zinc is brought into contact with an aqueous solution containing at least one of the elements selected from a group consisting of cobalt, nickel, tin, copper, titanium, and zirconium after the treatment liquid contact process.

It is a further object of the invention to provide a surface treatment method as described herein that includes a process in which the metal material that contains iron and/or zinc is brought into contact with an aqueous solution containing a water-soluble polymer compound or a water-dispersible polymer compound after the treatment liquid contact process.

Another object of the invention is an iron-containing metal material having a surface coating film layer, formed on the surface thereof by a surface treatment method as described herein, using a composition that contains the elements of Component (A) and the surface coating film layer has an adhesion quantity in terms of elements of greater than 20 mg/cm² or greater than 15 mg/cm².

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A composition for surface treatment of a metal, treating liquid for surface treatment, method of surface treatment, and surface-treated metal materials obtained by said treatment method of the present invention are techniques capable of depositing a surface coating film with excellent corrosion resistance after coating on the surface of the metal material using a treatment bath that contains none of the environmentally harmful components used in conventional techniques.

A composition for surface treatment of a metal of the present invention (also to be called simply “the composition of the present invention” in the following), a treatment liquid for metal surface treatment of the present invention (also to be called simply “the treatment method of the present invention” in the following), and a metal material containing iron and/or zinc of the present invention (also to be called simply “the metal material of the present invention” in the following) will now be described in more detail. The composition and the treatment liquid of the present invention will be explained first.

The composition of the present invention is diluted with water or dissolved in water at the time of its use to form the treatment liquid of the present invention.

The materials to be surface-treated with the treatment liquid of the present invention are iron-based metal materials or zinc-based metal materials.

There are no particular limitations with regard to the kind of iron-based metal materials that can be used as long as they contain iron. Suitable materials would include, for example, steel plate such as cold rolled steel plate, hot rolled steel plate, etc., cast iron, and sintered materials.

There are no particular limitations with regard to the kind of zinc-based metal materials that can be used as long as they contain zinc. Suitable materials would include, for example, zinc die-cast and zinc-containing plated materials. The zinc-containing plated materials consist of zinc or alloys of zinc and at least one other element selected from among, for example, nickel, iron, aluminum, manganese, chromium, magnesium, cobalt, lead, and antimony, and unavoidable impurities. There are no particular limitations with regard to the plating methods that can be used. Suitable methods would include, for example, electroplating methods, fusion plating methods, vapor deposition plating methods, etc.

The present invention pertains to surface treatment of the surface of metal materials. The metal materials can be surface-treated individually or combinations of two or more of them can be treated simultaneously. When two or more metal materials are to be treated simultaneously and when at least one of the metal materials is an iron- or zinc-based metal material, the other metal material can be aluminum, magnesium, nickel, or their alloys. Moreover, the different metals may not be in contact with each other or they can be in contact with each other or joined together by a welding, adhesion, riveting or other known methods. The functions of the present invention will now be described in detail.

A composition of the present invention contains Component (A), Component (B), and Component (C) as described below.

Component A is a compound containing at least one element selected from the group consisting of Ti, Zr, Hf, and Si. Suitable compounds include, for example, TiC14, Ti(SO₄)₂, TiOSO₄, Ti(NO₃)₄, TiO(NO₃)₂, Ti(OH)₄, TiO₂OC₂O₄, H₂TiF₆, salts of H₂TiF₆, TiO, TiO₂, Ti₂O₃, TiF₄, ZrCl₄, ZrOCl₂, Zr(OH)₂C1₂, Zr(OH)₃CI, Zr(SO₄)₂, ZrOSO₄, Zr(NO₃)₄, ZrO(NO₃)₂, Zr(OH)₄, H₂ZrF₆, salts of H₂ZrF₆, H₂(Zr(CO₃)₂(OH)₂, salts of H₂(Zr(CO₃)₂(OH)₂, H₂Zr(OH)₂(SO₄)₂, salts of H₂Zr(OH)₂(SO₄)₂, ZrO₂, ZrOBr₂, ZrF₄, HfCl₄, Hf(SO₄)₂, H₂HfF₆, salts of H₂HfF₆, HfO₂, HfF₄, H₂SiF₆, salts of H₂SiF₆ and A1₂O₃(SiO₂)₃. Two or more of these compounds may also be used together.

Component (B) is a compound containing yttrium and/or a lanthanide element; i.e., a compound containing at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Suitable compounds include, for example, oxides, sulfates, nitrates, and chlorides of these elements. More specifically, for example, suitable compounds include yttrium chloride, lanthanide chloride, cerium chloride, praseodymium chloride, neodymium chloride, promethium chloride, samarium chloride, europium chloride, gadolinium chloride, terbium chloride, dysprosium chloride, holmium chloride, erbium chloride, thulium chloride, ytterbium chloride, lutetium chloride, yttrium sulfate, lanthanide sulfate, cerium sulfate, praseodymium sulfate, neodymium sulfate, promethium sulfate, samarium sulfate, europium sulfate, gadolinium sulfate, terbium sulfate, dysprosium sulfate, holmium sulfate, erbium sulfate, thulium sulfate, ytterbium sulfate, lutetium sulfate, yttrium nitrate, lanthanide nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, promethium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, lutetium nitrate, yttrium oxide, lanthanide oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, and lutetium oxide. Two or more of these compounds may also be used together.

Component (C) comprises nitric acid and/or a nitric acid compound. Suitable compounds include, for example, nitric acid, metal nitrates, and the like. Metal nitrates include, for example, ferric nitrate, manganese nitrate, nickel nitrate, cobalt nitrate, silver nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, and calcium nitrate. Two or more of these compounds may also be used concomitantly.

A composition of the present invention is diluted with water or dissolved in water to form a treatment liquid at the time of its use for the surface treatment of a metal. In preparing the treatment liquid for metal surface treatment, water is added to the composition for metal surface treatment to bring the total mass concentration of elements (Ti, Zr, Hf. and Si) of Component (A) within the range of 10 ppm to 10,000 ppm.

The term “the total mass concentration “A” of elements contained in Component (A)” indicates “the concentration of elements contained in Component (A) contained in the composition (in some cases, the treatment liquid) of the present invention”. The terms “the total mass concentration B” and “the total mass concentration C” are interpreted in a like manner for their respective components.

In the composition for surface treatment and the treatment liquid for surface treatment of the present invention, the ratio “K1” of the total mass concentration “B” of the yttrium and/or lanthanide element contained in Component (B) to the total mass concentration “A” of the elements contained in Component (A), i.e., K1=B/A, is in the range of 0.05≦K1≦50 and the ratio “K2“of the total mass concentration “C” of the nitrogen atoms contained in Component (C) in terms of the NO₃ concentration to the total mass concentration “A”, i.e., K2=C/A, is in the range of 0.01≦K2≦200.

Here, component A is a substance having excellent anti-acid and anti-alkali properties and is the main component of the surface coating film of the present invention.

Component (B) can promote the film deposition of Component (A). Moreover, Component (B) may be contained in the surface coating film so that the corrosion resistance and bare corrosion resistance of the film after coating can be expected to further improve.

Component (C) in the treatment liquid for surface treatment serves to maintain the stability of the treatment liquid by increasing the solubility of Component (A) and Component (B). Furthermore, Component (C) can also assist the film deposition of Component (A), though not as effectively as Component (B).

When K1=B/A is too small, Component (B) can not be expected to promote the film deposition of Component (A) because of the reduced proportion of Component (B). Consequently, the amount of film adhesion of Component (A) will decrease compared to that obtained when the total mass concentration ratio of Component (A) to Component (B), i.e., K1, is within the range of 0.05≦K1<50 and the corrosion resistance of the treated metal material may decrease.

When K 1 is too large, the reaction initiation point itself of Component (A) on the surface of the treated metal material may be lowered and the amount of film adhesion of Component (A), that is the main component of the film and the component that provides the corrosion resistance to the film, will decrease even though the film deposition promoting effect of Component (B) is present. Therefore, excellent corrosion resistance cannot be obtained and the adherence may also be adversely affected in some cases where the ratio of B/A is outside of the above recited ranges.

When K2=C/A is too small, suitable corrosion resistance of the treated metal material cannot be obtained and the treatment liquid stability of the treatment liquid for surface treatment may be adversely affected. Consequently, continuous operation may be hindered. Furthermore, because of the small proportion of Component (C) in the treatment liquid, the assisting effect of Component (C) on the film deposition of Component (A) cannot be expected.

When K2=C/A is in the range of 0.01≦K2≦200, it will be sufficient to maintain the stability of the treatment liquid of the present invention. Larger K2 values will not improve the corrosion resistance and thus are economically disadvantageous.

The total mass concentration “A” of Component (A) used in the treatment liquid of the present invention is preferably adjusted to be in the range of 10 ppm to 10,000 ppm, and more preferably in the range of 50 ppm to 5,000 ppm or 100 ppm to 4,000 ppm. When the total mass concentration “A” is too small, it will become difficult to obtain an amount of adhesion sufficient for acquiring the desired corrosion resistance within a practical treatment time due to the low concentration of the film main component, even though KI and K2 are within the specified ranges. When the total mass concentration “A” is too large, although a sufficient amount of adhesion can be obtained, the corrosion resistance cannot be improved further and thus an excessively high total mass concentration “A” is not economically desirable.

It is desirable that the composition and treatment liquid of the present invention additionally contain at least one fluorine-containing compound as Component (D). Suitable compounds include, for example, hydrofluoric acid, H₂TiF₆, salts of H₂TiF₆, TiF₄, H₂ZrF₆, salts of H₂ZrF₆, ZrF₄, H₂HfF₆, salts of H₂HfF₆, HfF₄, H₂SiF₆, HBF₄, salts of HBF₄, NaHF₂, KHF₂, NH₄HF₂, NaF, KF, and NH₄F. Two or more of these fluorine-containing compounds may also be used concomitantly.

When Component (D) is to be added to the treatment liquid of the present invention, the concentration of at least one of the fluorine-containing compounds of Component (D) is preferably adjusted so that the free fluorine ion concentration D will be in the range of 0.001 ppm to 300 ppm, and more preferably in the range of 0.1 ppm to 100 ppm. Here, the term “free fluorine ion concentration D” means the fluorine ion concentration determined with the use of a commercially available ion electrode in a manner known in the art, see the Examples. When the free fluorine ion concentration D is too high, the etching reaction on the raw material surface by HF will be too excessive and the amount of film deposition sufficient to achieve corrosion resistance of the surface of the treated metal material will tend to become difficult to obtain. The corrosion resistance of the surface of the treated metal material can be achieved even when the free fluorine ion concentration “D” produced by the fluorine-containing compound of Component (D) is too small, but the stability of the treatment liquid for surface treatment may be adversely affected and continuous operation may be hindered.

Film deposition by the treatment liquid of the present invention is preferably induced by the formation reaction accompanying the etching of the metal base material. Therefore, the treatment is preferably carried out in a pH range in which an etching reaction will ordinarily occur, i.e., a pH value below 6.0, preferably below 5.0, and more preferably below 4.0.

There are no particular limitations with regard to the kind of reagent used for adjusting the pH of the treatment liquid of the present invention when needed. For example, acids such as hydrochloric acid, sulfuric acid, boric acid, and organic acids, alkalis such as lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, alkali metal salts, ammonia, ammonium salts, and amines may be used.

A treatment liquid of the present invention may be contaminated by the metals contained in the base material which are eluted out by the etching reaction of the base material, or by the metals or compounds contained in the tap water and industrial water because Component (B) can promote the film deposition of Component (A) and the film deposition of Component (A) will not be affected by other metal elements.

An anion component is preferably added to the treatment liquid of the present invention to further promote the film-formation reaction. Suitable anion components that may be added to the treatment liquid for surface treatment of the present invention include, for example, HCl, H₂SO₄, HClO₃, HBrO₃, HNO2, HMnO₄, HVO₃, H₂O₂, H₂WO₄, H₂MoO₄, and the like. There are no particular limitations with regard to the concentration of the anion component added; a concentration in the range of about 10 ppm to 20,000 ppm; preferably 20 tol5,000; most preferably 50 to 10,000 ppm, is sufficient for providing the desired effect.

When the treatment load of the metal material to be treated is high for the treatment liquid of the present invention, a chelating agent capable of chelating metal ions dissolved out by the etching reaction is preferably added. Suitable chelating agents that can be used in the treatment liquid of the present invention include, for example, ethylenediamine tetraacetic acid (EDTA), gluconic acid, heptogluconic acid, glycolic acid, citric acid, succinic acid, fumaric acid, aspartic acid, tartaric acid, malonic acid, malic acid, salicylic acid, and their salts. There are no particular limitations with regard to the content of these chelating agents. For example, a concentration in the range of about 1 ppm to 10,000 ppm; preferably 10 ppm to 9,000 ppm; most preferably 20 ppm to 7,500 ppm, is sufficient for providing the desired effect. [0058.] A water-soluble polymer compound and/or a water-dispersible polymer compound having an ionic reactive group in their molecule are preferably added to the treatment liquid of the present invention. Suitable compounds include, for example, copolymers of polyvinyl alcohol, poly(meth)acrylic acid or acrylic acid, and methacrylic acid, copolymers of ethylene and acryl-type monomers such as (meth)acrylic acid, (meth)acrylate, etc., copolymers of ethylene and vinyl acetate, polyurethane, amino modified phenol resins, polyester resins, epoxy resins, polyamide amines, polyamines, polyamine derivatives, polyallyl amines, polyallyl amine derivatives, polyamide amine derivatives, polyvinyl amine, polyvinyl amine derivatives, tannin, tannic acid and its salts, and phytic acid. There are no particular limitations with regard to the concentration of compounds added, but a concentration in the range of 1 ppm to 10,000 ppm; preferably 10 to 9,000; most preferably 20 to 7,500 ppm, is preferable. This addition quantity should give a sufficient effect.

At least one surfactant selected from a group consisting of nonionic surfactants, anionic surfactants, and cationic surfactants is preferably added to the treatment liquid of the present invention. When a treatment liquid for surface treatment of this kind is used for the surface treatment of a metal base material, as will be mentioned later, a good film can be formed without a preliminary degreasing treatment or cleansing treatment of the metal material to be treated. Namely, the treatment liquid for surface treatment of the present invention can be used as a degreasing surface treatment agent as well as a formation surface treatment agent.

The treatment method of the present invention is a surface treatment method for metals containing iron and/or zinc that includes a treatment liquid contact process in which the metal material containing iron and/or zinc is brought into contact with the treatment liquid of the present invention.

The only requirement of the surface treatment method of the present invention is to contact the metal material containing iron and/or zinc with the treatment liquid of the present invention. In this way a film made of oxides and/or hydroxides of the elements of Component (A) will be deposited on the surface of the metal base material and a surface coating film layer with excellent adherence and corrosion resistance can thus be formed.

Any method such as a spray treatment, immersion treatment, or other treatment methods know in the art can be used for the contact treatment mentioned above; the contact method used will not affect the performance of the film formed.

It is chemically difficult to obtain the hydroxide of metals contained in the film of Component (A) in the form of a pure hydroxide. In general, therefore, oxides of the metals with attached water of hydration are also included in this group of oxides. Therefore, the hydroxides of metal will eventually become oxides by heating. As for the structure of the surface coating film of the present invention, it is believed that the film is present in the state of a mixture of oxides and hydroxides when the film is dried at normal temperature or a low temperature after the surface treatment, whereas the film is present in a state in which oxides only or oxides as the majority component are present when the film is dried at a high temperature after the surface treatment.

The metal material containing iron and/or zinc is preferably subjected to a cleansing process, such as a degreasing treatment. There are no particular limitations with regard to the method used for degreasing, i.e., any conventional method can be used.

As mentioned before, when the treatment liquid of the present invention contains surfactant, a good film can be formed even without pre-cleansing of the metal material containing iron and/or zinc by a degreasing treatment. Namely, in this case, the degreasing treatment and the film-forming treatment of the metal material containing iron and/or zinc are carried out at the same time.

There are no particular limitations with regard to the conditions of use of the treatment liquid of the present invention.

The reactivity of the treatment liquid of the present invention can be controlled freely by changing the ratio “K1“of the total mass concentration “B” to the total mass concentration “A”, i.e., K1=B/A, and the ratio “K2” of the total mass concentration “C” to the total mass concentration “A”, i.e., K2=C/A.

Furthermore, even when at least one of Component (D) fluorine-containing compounds is used, the reactivity can still be controlled by changing the free fluorine ion concentration “D”. The treatment temperature and treatment time can be altered freely in accordance with the reactivity of the treatment bath.

In the treatment method of the present invention, an electrolytic treatment with the metal material containing iron and/or zinc as the cathode can be carTied out while the metal material is in the state of contact with the treatment liquid of the present invention. In this case, a hydrogen reducing reaction will occur at the interface of the metal material containing iron and/or zinc serving as the cathode and the pH will rise. With a rising pH, the stability of the compound containing the elements of Component (A) at the cathode interface will decrease and the surface treatment film will be deposited as an oxide or as a water-containing hydroxide.

After the metal material containing iron and/or zinc has made contact with the treatment liquid of the present invention or has been subjected to an electrolytic treatment during such contact, it may then be brought into contact with an acidic aqueous solution containing at least one element selected from a group consisting of cobalt, nickel, tin, copper, titanium, and zirconium or with a treatment solution containing at least one water-soluble polymer compound and/or water-dispersible polymer compound. In this way, the effect of the present invention can be further enhanced.

A surface coating film obtained by the present invention is a thin film with excellent coating performance. When the surface condition of the metal material to be treated shows the presence of an abnormality, the surface treatment film layer may end up with a very small defective portion. Therefore, the metal material is brought into contact with the acidic aqueous solution containing at least one element selected from a group consisting of cobalt, nickel, tin, copper, titanium, and zirconium or with a treatment solution containing at least one water-soluble polymer compound and/or water-dispersible polymer compound. In this way, any defective portion can be covered and the corrosion resistance can be further improved.

There are no particular limitations with regard to the source of supply of the at least one element selected from a group consisting of cobalt, nickel, tin, copper, titanium, and zirconium. Readily available oxides, hydroxides, fluorides, complex fluorides, chlorides, nitrates, oxynitrates, sulfates, oxysulfates, carbonates, oxycarbonates, phosphates, oxyphosphates, oxalates, oxyoxalates, and organometal compounds of the metal elements can be used. The acidic aqueous solution containing the metal elements preferably has a pH value in the range of 2-6. Acids such as phosphoric acid, nitric acid, sulfuric acid, hydrofluoric acid, hydrochloric acid, and organic acids, and alkalis such as sodium hydroxide, potassium hydroxide, lithium hydroxide, alkali metal salts, ammonia, ammonium salts, and amines can be used for pH adjustment.

The at least one polymer compound selected from among water- soluble polymer compounds and water-dispersible polymer compounds can be, for example, a copolymer of polyvinyl alcohol, poly(meth)acrylic acid or acrylic acid, and methacrylic acid, copolymers of ethylene and acryl-type monomers such as (meth)acrylic acid, (meth)acrylate, etc., copolymers of ethylene and vinyl acetate, polyurethane, amino modified phenol resins, polyester resins, epoxy resins, polyamide amines, polyamines, polyamine derivatives, polyallyl amines, polyallyl amine derivatives, polyamide amine derivatives, polyvinyl amine, polyvinyl amine derivatives, tannin, tannic acid and its salts, and phytic acid.

As was described in detail above, with the present invention, the corrosion resistance of a metal material can be improved markedly by forming a film layer made of the oxides and/or hydroxides of Component (A) or a film layer made of a mixture of film layers consisting of the film layer of Component (A) and a film layer made of the oxides and/or hydroxides of the metal elements of Component (B). Here, any films made of the oxides and/or hydroxides of Component (A) are acid and alkali resistant and are chemically stable.

Here, in the actual coated film corrosion environment of a metal, the pH will decrease at the anode portion where the elution of metals takes place and the pH will increase at the cathode portion where a reduction reaction occurs. Therefore, a surface coating film with poor acid and alkali resistance will be dissolved in a corrosive environment and lose its effectiveness. A film made of the oxides and/or hydroxides of Component (A) used in the present invention is resistant to both acids and alkalis. In addition, with the present invention, a thin and uniform surface coating film can be formed on the surface of the metal to be treated and thus the superior effect of the present invention can be maintained even in a corrosive environment.

Since the oxides and hydroxides of the metal elements contained in the film can form a network structure through metals and oxygen, the formed film is an excellent barrier film. The corrosion of a metal material will vary depending on the environment in which the metal material is used. In general, however, corrosion will occur under the condition where water and oxygen are present and thus is usually of the oxygen requiring type. Therefore, the corrosion speed will be increased in the presence of components such as chlorides, etc. Since the film layer of the present invention has a barrier effect on water, oxygen, and corrosion-promoting components, it offers an excellent anti-corrosion property.

In addition to Component (A) and Component (B), the composition and the treatment liquid of the present invention may also contain Component (C), the proportions of which are set to be within specified ranges. Therefore, at the time of deposition of the surface coating film, a formation reaction will also occur. The accompanying formation reaction can sharply increase the adherence property of the film.

Here, in order to utilize the barrier effect to increase the corrosion resistance of iron-based metal materials such as cold rolled steel plate, hot rolled steel plate, cast iron, sintered materials, etc., the adhering amount of the surface coating film in terms of Component (A) is preferably greater than 20 mg/m², more preferably greater than 30 mg/m², and especially greater than 40 mg/m².

Moreover, in order to increase the corrosion resistance of zinc-based metal materials such as zinc or zinc plated steel plate, zinc electroplated steel plate, etc., the adhering amount of the surface coating film in terms of Component (A) is preferably greater than 15 mg/m², and more preferably greater than 20 mg/m².

When the adhering amount is too small, the barrier effect will not be sufficient and it will be difficult to obtain excellent corrosion resistance.

There are no particular limitations with regard to the upper limit of the adhering amount on the iron-based metal material or zinc-based metal material. However, when the adhesion amount is too large, cracks will readily from in the surface coating film and the process of trying to form a uniform film will become difficult. Therefore, the adhering amount in terms of Component (A) for both iron-based materials and zinc-based materials is preferably no more than 1 g/m², and especially no more than 800 mg/m².

The invention and its benefits will be better understood with reference to the following examples. These examples are intended to illustrate specific embodiments within the overall scope of the invention as claimed, and are not to be understood as limiting the invention in any way.

ACTUAL EXAMPLES

The effect of the surface treatment liquid and the surface treatment method of the present invention will now be explained in detail with the use of actual examples and comparison examples. The material to be treated, the degreasing agent, and the coating material used were selected arbitrarily from among commercially available products and should not restrict in any way the actual use of the surface treatment liquid and the surface treatment method.

Plates Used for the Study

The code designations and description of the plates used in the actual examples and comparison examples are given below.

-   -   SPC (cold rolled steel plate; JIS-G-3141)     -   EG (zinc electroplated steel plate; plating quantity 20 g/m²)         Treatment Process

The surface treatment in Actual Examples 1-5 and Comparison Examples 1-3 was carried out in accordance with the following treatment process: Alkaline degreasing→water washing→film formation treatment→water washing deionized→water washing drying.

In Actual Example 6, the surface treatment was carried out in accordance with the following treatment process: Alkaline degreasing→water washing→film formation treatment→water washing→post treatment→deionized water washing→drying.

In Actual Example 7, the surface treatment was carried out in accordance with the following treatment process: Alkaline degreasing→water washing→electroformation treatment→water washing→deionized water washing→drying.

In Comparison Example 4, the surface treatment was carried out in accordance with the following treatment process: Alkaline degreasing→water washing→surface preparation→water washing→deionized water washing→drying.

For the alkaline degreasing treatment employed in both the actual examples and comparison examples, Fine Cleaner L4460A (registered trade name, manufactured by Nihon Parkerizing Co., Ltd.) and Fine Cleaner L4460B (registered trade name, manufactured by the Nihon Parkerizing Co., Ltd.) diluted with tap water to 2% and 1.4%, respectively, were sprayed on the plate to be treated at 40° C. for 120 seconds.

For the water washing and deionized water washing treatments in both the actual examples and comparison examples, water and deionized water, respectively, were sprayed on the plate to be treated at room temperature for 30 seconds.

The plate was then dried by allowing it to stand in a room at room temperature.

Actual Example 1

An aqueous zirconium sulfate solution, lanthanide sulfate, and nitric acid were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=0.1 and a total mass concentration ratio K2=C/A=0.01. This composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 8,000 ppm. Sodium hydroxide was then added to obtain a surface treatment liquid with a pH value of 3.2. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 50° C. for 180 seconds for surface treatment.

Actual Example 2

An aqueous hexafluoro zirconium solution, samarium nitrate, and nitric acid were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=2.0 and a total mass concentration ratio K2=C/A=50. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 100 ppm. Hydrofluoric acid and ammonia were then added to obtain a surface treatment liquid with a free fluorine concentration of 25 ppm (as measured according to the manufacturer's instructions with fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 3.6. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 45° C. for 150 seconds for surface treatment.

Actual Example 3

An aqueous zirconium nitrate solution, hafnium oxide, gadolinium oxide, and potassium nitrate were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=5.0 and a total mass concentration ratio K2=C/A=20. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium and the mass concentration of hafnium to a combined mass concentration of 50 ppm. 100 ppm of succinic acid was added to the liquid thus obtained. Potassium fluoride and lithium hydroxide were added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 20 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 4.0. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 60° C. for 120 seconds for surface treatment.

Actual Example 4

An aqueous zirconium nitrate solution, an aqueous lanthanum chloride solution, erbium oxide, sodium nitrate, and nitric acid-soda were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=35 and a total mass concentration ratio K2=C/A=100. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 20 ppm. Hydrofluoric acid and calcium hydroxide were then added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 15 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 3.0. A test plate that had been degreased and water-washed was sprayed with the surface treatment liquid at 55° C. for 120 seconds for surface treatment.

Actual Example 5

An aqueous titanium nitrate solution, an aqueous hexafluoro silicate solution, praseodymium oxide, and potassium nitrate were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=0.4 and a total mass concentration ratio K2=C/A=8.0. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium and the mass concentration of the silicon to a combined mass concentration of 2,500 ppm. Ammonium fluoride and ammonia were then added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 100 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 2.9. A test plate that had been degreased and water-washed was sprayed with the surface treatment liquid at 65° C. for 300 seconds for surface treatment.

Actual Example 6

An aqueous zirconium nitrate solution, an aqueous hexafluoro titanium solution, lanthanum chloride, and iron nitrate were used to prepare a composition for surface treatment with a total mass concentration ratio K1=B/A=1.0 and a total mass concentration ratio K2=C/A=0.5. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium and the mass concentration of the titanium to a combined mass concentration of 200 ppm. Ammonium fluoride and potassium hydroxide were then added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 50 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 4.2. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 60° C. for 200 seconds for surface treatment. After water washing, the plate was subjected to a post treatment. As for the post treatment liquid used, an aqueous hexafluoro titanium solution and nickel nitrate were used to prepare an aqueous solution with a titanium mass concentration of 200 ppm and a nickel mass concentration in terms of the metal element of 50 ppm. This aqueous solution was heated to 45° C. and then sodium hydroxide was used to adjust its pH to 4.5. The solution thus obtained was used in the post treatment.

Actual Example 7

An aqueous hexafluoro zirconium solution, yttrium sulfate, and nitric acid were used to prepare a composition for surface treatment with a total mass concentration ratio “K1”=B/A=3.0 and a total mass concentration ratio “K2”=C/A=3.0. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 200 ppm. 50 ppm of EDTA was added to the liquid, then hydrofluoric acid and sodium hydroxide were added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 80 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 2.8. A test plate that had been degreased and water-washed was used as a cathode and a carbon electrode was used as an anode to carry out electrolysis cathodic electro deposition at a current density of 5 A/dm² in the surface treatment liquid at room temperature for 10 seconds for surface treatment.

Comparison Example 1

An aqueous zirconium nitrate solution and nitric acid were used to prepare a composition for surface treatment with a total mass concentration ratio “K1”=B/A=0.01 and a total mass concentration ratio “K2”=C/A=10. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 100 ppm. Sodium hydroxide was then added to obtain a treatment liquid for surface treatment with a pH value of 3.0. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 55° C. for 180 seconds for surface treatment.

Comparison Example 2

An aqueous hexafluoro zirconium solution, europium oxide, and sodium nitrate were used to prepare a composition for surface treatment with a total mass concentration ratio “K1”=B/A=5.0 and the total mass concentration ratio “K2”=C/A=200. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the zirconium to 4 ppm. Potassium fluoride and potassium hydroxide were then added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 20 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 3.8. A test plate that had been degreased and water-washed was immersed in the surface treatment liquid at 60° C. for 120 seconds for surface treatment.

Comparison Example 3

An aqueous hexafluoro titanium solution, gallium sulfate, potassium nitrate, and ammonium nitrate were used to prepare a composition for surface treatment with a total mass concentration ratio “K1”=B/A=70 and a total mass concentration ratio “K2”=C/A=50. The composition for surface treatment was diluted with deionized water to adjust the mass concentration of the titanium to 50 ppm. Ammonium fluoride and ammonia were then added to obtain a treatment liquid for surface treatment with a free fluorine concentration of 400 ppm (fluorine ion meter: IM-55G, manufactured by Toa Denpa Kogyo Co., Ltd.) and a pH value of 2.8. A test plate that had been degreased and water-washed was sprayed with the surface treatment liquid at 50° C. for 150 seconds for surface treatment.

Comparison Example 4

A test plate that had been degreased and water-washed was sprayed at room temperature for 30 seconds with a liquid obtained by diluting Prepalene ZN (registered trade name, manufactured by the Nihon Parkerizing Co., Ltd.) (a surface preparation agent) to 0.1% with tap water. The test plate was then immersed in a zinc phosphate formation treatment liquid at 43° C. for deposition of a zinc phosphate film. The zinc phosphate formation liquid was prepared as follows: Palbond L3020 (registered trade name, manufactured by the Nihon Parkerizing Co., Ltd.) was diluted with tap water to 4.8%. A sodium hydrofluoride reagent in a quantity equivalent to 200 ppm of fluorine was then added to the diluted Palbond at 43° C. and the total acidity and free acidity were adjusted to the specified values provided by the Palbond manufacturer for use.

Evaluation of Surface Coating Film and Measurement of Adhering Quantity

The external appearances of the test plates obtained in accordance with the actual examples and comparison examples after the surface treatment were evaluated visually by the naked eye. The adhering quantity of the surface coating film layer in g/m² was determined with the use of a fluorescence X-ray analyzer (System 3270, manufactured by Rigaku Denki Kogyo Co., Ltd.) as in known in the art.

Preparation of the Plate for Evaluation of Coating Performance

In order to evaluate the coating performance of the surface treatment plates obtained from the actual examples and comparison examples, the coating was carried out according to the following process: cation electrodeposition→deionized water washing→baking→midcoat application→baking→topcoat application→baking.

-   Cation Electrodeposition: epoxy-based cation electrodeposition     coating material (Elecron 9400, manufactured by Kansai Paint Co.,     Ltd.), voltage 200 V, film thickness 20 μm, baking at 175° C. for 20     minutes. -   Midcoat Application: aminoalkyd-based coating material (Amilac TP-37     White, manufactured by Kansai Paint Co., Ltd.), spray coating, film     thickness 35 μm, baking at 140° C. for 20 minutes. Topcoat     Application: aminoalkyd-based coating material (Amilac TM- 13 Gray,     manufactured by Kansai Paint Co., Ltd.), spray coating, film     thickness 35 μm, baking at 140° C. for 20 minutes.     Coating Performance Evaluation

The coating performance of the actual examples and comparison examples was evaluated according to the above mentioned JIS specification. The evaluation items are described below. The coated film obtained at the time of completion of the electrodeposition coating was called the electrodeposition coated film and the coated film obtained at the time of completion of the topcoat application was called a 3-coat coated film.

-   -   (i) Salt Spray Test: electrodeposition coated film     -   (ii) Adherence Test: 3-coat coated film         Salt Spray Test (SST)

A crosscut was made with the use of a sharp cutter on the electrodeposition coating plate. This plate was sprayed with 5% salt water for 720 hours (according to JIS-Z-2371). After spraying, the widths of the maximum swelling from both sides of the crosscut area were measured and evaluated according to the following evaluation standards: Width of Maximum Swelling no more than 5 mm ⊚ greater than 5 mm but no more than 7 mm ◯ greater than 8 mm but no more than 9 mm Δ greater than 9 mm X Adherence Test (Crosscut Method)

A sharp cutter was used to make 6 cuts in both the vertical and horizontal directions at 2 mm interval on the 3-coat coated film to obtain 25 squares (according to JIS-K-5600-5-6). Adhesive tape was applied to the cut surface and then removed as per JIS specification. Any squares were peeled off by a tape and evaluated by the evaluation method according to the JIS specification.

The results of evaluation of the external appearances of test plates obtained from the actual examples and comparison examples and the adhering quantity of the surface coating film are summarized in Table 1 and Table 2. The SPC materials and EG materials obtained from the actual examples all gave a uniform film and the targeted film adhering quantity could be attained.

In contrast, the deposition of a surface coating film could not be achieved on either the SPC materials or the EG materials obtained from Comparison Example 1 because of the small value of the total mass concentration ratio “K1”. Deposition of a surface coating film was also not possible on either the SPC material or the EG material obtained from Comparison Example 2 because of the small content of Component (A). Deposition of a surface coating film was also not possible on either the SPC material or the EG material obtained from Comparison Example 3 because of the large value of the total mass concentration ratio “K1” and the high free fluorine ion concentration “D”. Formation of a surface coating film was possible on the SPC material and the EG material obtained from Comparison Example 4 because a conventional zinc phosphate treatment was employed in this example.

Table 3 shows the results of coating performance evaluation of the electrodeposition-coated film. The SPC material and EG material obtained from the actual examples all showed excellent corrosion resistance. In contrast, the promoting effect of Component (B) on the film formation of Component (A) was not sufficient in Comparison Example 1 because of the small value of the total mass concentration ratio “K1”. Accordingly, there was not very much deposition of a surface coating film on either the SPC material or the EG material and the corrosion resistance of the deposited film was poor.

For the SPC material and the EG material obtained from Comparison Example 2, the targeted adhering quantity could not be achieved and the corrosion resistance was poor because the content of Component (A) was too low. For the SPC material and the EG material obtained from Comparison Example 3, the targeted adhering quantity could not be achieved and the corrosion resistance was poor because the total mass concentration ratio “K 1” was too large and the free fluorine ion concentration “D” was too high. In Comparison Example 4, a zinc phosphate treatment commonly used for cation electrodeposition coating was employed. The coating performances obtained from the actual examples were all superior to those obtained from Comparison Example 4 at all levels.

Table 4 shows the results of evaluation of the adherence property of the 3-coat plate. The adherence property with regard to all the test plates used in the actual examples was excellent. For the comparison examples, as in the case of the corrosion resistance of the electrodeposition coated plate, the adherence property with regard to the test plates used in all the comparison examples except for Comparison Example 4 was not as good as that obtained with the actual examples.

It can be seen from the results mentioned above that, with the use of the composition for surface treatment, the treatment liquid for surface treatment, the surface treatment method, and the surface treated metal material of the present invention, the deposition of a surface coating film with excellent adherence and excellent corrosion resistance becomes possible. TABLE 1 External Appearance of Treatment Film SPC EG Actual Example 1 uniform interference color uniform surface color Actual Example 2 uniform interference color uniform surface color Actual Example 3 uniform interference color uniform surface color Actual Example 4 uniform interference color uniform surface color Actual Example 5 uniform interference color uniform surface color Actual Example 6 uniform interference color uniform surface color Actual Example 7 uniform interference color uniform surface color Comparison no deposition no deposition Example 1 Comparison no deposition no deposition Example 2 Comparison no deposition no deposition Example 3 Comparison uniform gray color uniform gray color Example 4

TABLE 2 Total Adhesion Quantity of COMPONENT (A) SPC EG Actual Example 1 60 41 Actual Example 2 100 78 Actual Example 3 65 41 Actual Example 4 20 16 Actual Example 5 45 32 Actual Example 6 90 75 Actual Example 7 50 42 Comparison Example 1 6 3 Comparison Example 2 4 2 Comparison Example 3 5 3 Comparison Example 4 ※2.0 g/m² ※4.2 g/m² ※adhering quantity of zinc phosphate

TABLE 3 Electrodeposition Plate, SST Results SPC EG Actual Example 1 ⊚ ◯ Actual Example 2 ⊚ ◯ Actual Example 3 ⊚ ◯ Actual Example 4 ⊚ ◯ Actual Example 5 ⊚ ◯ Actual Example 6 ⊚ ◯ Actual Example 7 ⊚ ◯ Comparison Example 1 X X Comparison Example 2 X X Comparison Example 3 X X Comparison Example 4 ⊚ ◯

TABLE 4 Adherence Property (Cross Cut Method) ※Evaluation According to JIS K-5600-5-6 SPC EG Actual Example 1 0 0 Actual Example 2 0 0 Actual Example 3 0 0 Actual Example 4 0 0 Actual Example 5 0 0 Actual Example 6 0 0 Actual Example 7 0 0 Comparison Example 1 2 1 Comparison Example 2 2 2 Comparison Example 3 2 2 Comparison Example 4 0 0

This invention relates to a composition for surface treatment, and processes for using this product. It can be used in many variations of the processes that are employed industrially. While the invention has been described in terms of specific embodiments thereof, it will be appreciated that other forms could readily be adapted by one skilled in the art. Accordingly, the scope of the invention is to be considered limited only by the following claims. 

1. A composition for the surface treatment of metals that comprises: (A) a compound containing at least one element selected from the group consisting of Ti, Zr, Hf, and Si; (B) a compound containing yttrium and/or a lanthanide element; (C) nitric acid and/or a nitric acid compound; and (D) an optional component of at least one fluorine-containing compound.
 2. The composition for surface treatment as claimed in claim 1, having a ratio “K1” of total mass concentration “B” of the yttrium and/or lanthanide element of Component (B) to total mass concentration “A” of the at least one element of Component (A) in the range of 0.05≦K1≦50 and a ratio “K2“of the total mass concentration “C” of the nitrogen atoms contained in Component (C), in terms of the NO₃ concentration, to the total mass concentration “A”, in the range of 0.01≦K2≦200.
 3. The composition for surface treatment as claimed in claim 1 comprising a treatment liquid that contains Component (D), at least one fluorine-containing compound, in an amount such that the free fluorine ion concentration “D” is in the range of 0.001 ppm<D<300 ppm.
 4. The treatment liquid for surface treatment as claimed in claim 3 having a pH value no greater than 6.0.
 5. The treatment liquid for surface treatment as claimed in claim 3 further comprising at least one compound selected from a group consisting of HCl, H₂SO₄, HClO₃, HBrO₃, HNO₂, HMnO₄, HVO₃, H₂O₂, H₂WO₄, H₂MoO₄, and their salts in a concentration in the range of 10-20,000 ppm.
 6. The treatment liquid for surface treatment as claimed in claim 3 further comprising at least one compound selected from a group consisting of ethylenediamine tetraacetic acid, gluconic acid, heptogluconic acid, glycolic acid, citric acid, succinic acid, fumaric acid, aspartic acid, tartaric acid, malonic acid, malic acid, salicylic acid, and their salts in a concentration in the range of 1-10,000 ppm.
 7. The treatment liquid for surface treatment as claimed in claim 3 further comprising at least one water-soluble polymer compound and/or a water-dispersible polymer compound.
 8. The treatment liquid for surface treatment as claimed in claim 3 further comprising at least one surfactant selected from a group consisting of nonionic surfactants, anionic surfactants, and cationic surfactants.
 9. A treatment method for metal material comprising iron and/or zinc comprising: contacting a metal material comprising iron and/or zinc with an acidic treatment liquid that comprises: (A) a compound containing at least one element selected from the group consisting of Ti, Zr, Hf, and Si; (B) a compound containing yttrium and/or a lanthanide element present in an amount such that ratio “K1” of total mass concentration “B” of the yttrium and/or lanthanide element of Component (B) to total mass concentration “A” of the at least one element of Component (A) is in the range of 0.05≦K1≦50; (C) nitric acid and/or a nitric acid compound present in an amount such that ratio “K2” of the total mass concentration “C” of the nitrogen atoms contained in Component (C), in terms of the N0₃ concentration, to the total mass concentration “A”, is in the range of 0.01≦K2≦200; and (D) at least one fluorine-containing compound in an amount such that the free fluorine ion concentration “D” in the treatment liquid is in the range of 0.001 ppm≦D≦300 ppm.
 10. The surface treatment method as claimed in claim 9 in which the metal material containing iron and/or zinc is contacted with the treatment liquid thereby simultaneously carry out a degreasing treatment and a film formation treatment of said metal material.
 11. The surface treatment method as claimed in claim 9 in which the metal material containing iron and/or zinc is a metal material that has been cleansed by a degreasing treatment.
 12. The surface treatment method as claimed in claim 9 in which the treatment liquid contact process comprises an electrolytic treatment using the metal material containing iron and/or zinc as the cathode.
 13. The surface treatment method as claimed in claim 9 further comprising a step of contacting the metal material with an aqueous solution containing at least one element selected from a group consisting of cobalt, nickel, tin, copper, titanium, and zirconium after the treatment liquid contact process.
 14. The surface treatment method as claimed in claim 9 further comprising a step of contacting the metal material with an aqueous solution containing a water-soluble polymer compound or a water-dispersible polymer compound after the treatment liquid contact process.
 15. An iron-containing metal material having a surface coating film layer, that is formed on the surface of the iron-containing metal material by a surface treatment method as claimed in claim 9, said surface coating film layer comprising at least one element of Component (A) in an amount of greater than 20 mg/cm².
 16. A zinc-containing metal material having a surface coating film layer, that is formed on the surface of the zinc-containing metal material by a surface treatment method as claimed in claim 9, said surface coating film layer comprising at least one element of Component (A) in an amount of greater than 15 mg/cm².
 17. A surface treatment method comprising contacting a metal material containing iron and/or zinc with the treatment liquid for surface treatment as claimed in claim
 3. 